


Garreg Mach Academy For Domestic Housemates

by ChubBee (NotSoBusyBee)



Category: Fire Emblem Series, Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Alternate Universe - Everyone Lives/Nobody Dies, Alternate Universe - No War, Animal Traits, Feeding Kink, Hybrids, Master/Pet, Multi, No Smut, Platonic Soulmates, Soul Bond, Weight Gain, a looser take on soulmates, but pets aren't slaves, chub kink
Language: English
Status: In-Progress
Published: 2019-10-01
Updated: 2019-10-01
Packaged: 2020-11-09 11:24:58
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,484
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20852651
Author URL: https://archiveofourown.org/users/NotSoBusyBee/pseuds/ChubBee
Summary: In which Byleth is suddenly roped into teaching a class of cute, chubby animal hybrids about how to be good pets and companions for their future families.But they're awfully adorable, and they sure do seem to like Byleth an awful lot... Not to mention, Byleth just loves spoiling them, especially with treats.So what happens if they all end up becoming so close that they'd rather just stay with Byleth instead?Weight gain/petplay AU where society operates under a consensual master/pet dynamic between humans and hybrids.  However, pets are not slaves, and must still be respected.As further warning, there's also teacher/student stuff, but all characters are 20 and up. It's more like a college than a high school.Still, if you're uncomfortable, please don't read.





	Garreg Mach Academy For Domestic Housemates

**Author's Note:**

> This is more of a general setup chapter, more detailed scenarios and more focus on individual characters will happen once I continue. There is at least already actual weight gain though... I didn't want to frustrate people by starting a weight gain fic but not having any actual weight gain yet, then making everyone wait a really long time for it.

  
In another version of Fodlan, all was well. There was no talk of war, no evil plot stirring beneath the surface.  
  
Instead, there were a variety of animal hybrids. Some who were essentially just like anyone else, and many who desired to become pets to humans. Towards that end, there were places to train them. And above all of them stood the Garreg Mach Academy for Domestic Housemates, giving hybrids a loving environment to become the best pets they could be.  
  
But regardless, it’d come to be common knowledge that ‘pet’ was a purely colloquial term. In any formal context, ‘domestic housemate’ would be used instead, to make it clear that hybrids were never to actually be regarded as animals or slaves.  
  
Hybrids took on the task of being a ‘pet’ as something more akin to a willing job rather than an obligation.  
  
Although it was often unpaid, there was still a strong expectation for the owner to do their best to provide whatever a hybrid needed to be happy, rather than only what they needed to survive. It was entirely within rights for ‘pets’ to have complaints and be picky about who could adopt them.  
  
In the event of mistreatment, hybrids were fully allowed to leave on their own, with various programs designed to support them in such an event. The term ‘ownership’ was also used colloquially, but it was common knowledge that such a term had no legal bearing and was ideally only used with full consent.  
  
The arrangement largely carried on in spite of continued controversy because, when done properly, most hybrids actually enjoyed and naturally sought humans who would care for them.  
  
Most commonly, the arrangements were decided through a phenomenon simply called ‘links’.  
  
Although similar to the concept of a soulmate, a ‘link’ was somewhat looser. It was not inherently romantic, not etched in fate, one person could have multiple, and they were not necessarily unbreakable. Every hybrid was link-compatible with a small fraction of the human population, and vice-versa. The link would typically become apparent after spending at least an hour or two together.

Although not strictly necessary for life or health, most of the population naturally craved at least one link.  
  
Typically, they were lifelong, and did not break or degrade on their own… but profound mental changes in a participant were able to change their link compatibility as well. Links did not account for fate or the future, only for the current traits of the people involved.  
  
A link created an empathetic bond between the participants, making them able to transfer feelings and emotions, as well as creating strong feelings of comfort and well-being. Links were even able to subtly make their participants stronger and healthier over time, reducing the risk of many diseases as well as being able to reduce pain, stress, and general inflammation.  
  
Such effects were at their strongest if the participants were able to frequently nurture and indulge in the link, spending time together and expressing physical affection. Therefore, they created a natural incentive for humans and hybrids to co-exist on a close basis, and were part of the reason why many hybrids had a natural drive to become pets. Regardless, the desire to become one was still separate from the desire to form links. It was thought that links evolved in the first place in order to encourage cooperation and harmony between the two species. Meanwhile, the master and pet relationship was more cultural, although it also had natural roots in helping the two species survive and get along better.  
  
Although there was nothing legally preventing a human from deciding to become a pet as well, and they could even go so far as to be magically transformed into a hybrid themself, it was a very rare occurrence, since humans mostly lacked the natural instinct to become pets. Not even all hybrids inherently wanted to be pets.  
  
Still, the way the system currently worked was flexible enough that everyone was reasonably happy with it. Those who wanted to be pets and those who didn't respected one another's wishes, and that was that.

* * *

But then there came a time when Garreg Mach was suddenly interested in finding a new teacher...  
  
Byleth had thought their work was definitely cut out for them when the task unexpectedly fell to them, through a twist of fate.  
  
How were they possibly supposed to go about teaching them all to be good pets?  
  
Pet education was different from regular education. Although hybrid children remained with their parents until adulthood, most could tell from an early age if they wanted to become pets or not. So, pets typically only learned normal topics up to a 6th-grade level before having the ability to switch over to focusing on how to be good pets. Hybrids were free to change their minds and decide to pursue normal education at any point, but most stuck with it.  
  
The ‘usefulness’ of pets varied, but it was considered wrong to force them into any labor beyond simple chores. If a pet was performing any professional roles on top of their ‘pet’ role, it had to be a mutual agreement, and the law required them to be fairly compensated for it. The pet role itself merely required being cute, friendly, and emotionally supportive… if anything, many people actually _ preferred _ them to be a bit ‘dumb’.   
  
So, about half of a pet’s teachings were domestic skills, and the other half were people skills. The academy was for adults, so it also offered training for plenty of more specialized skills as well.  
  
Still, Byleth was at least happy that basic pet school tended to be easy and laid back as well. The students had two hours of standard classes a day, and the specialist classes were typically just an extra hour every other weekday. Keeping the pets in high spirits was considered to be just as important as teaching them. People preferred them to be cheerful and affectionate, so avoiding undue stress by keeping things simple was a top priority.  
  
Byleth ended up choosing the Blue Lions house, relieved when things truly did start off relatively simple.  
  
And Byleth really hadn’t expected them to be so… cute. They were all dressed in the academy uniform consisting of comfortable but somewhat clingy light blue lounge-wear, along with collars made of pretty blue satin to designate them as part of the Blue Lion house.  
  
It was clear they must’ve been taught quite well already, as each student gave a polite introduction and some even happily offered themselves for pats on the head and tummy rubs. They already seemed very trusting.  
  
They were all already a bit on the plump side too, ranging from moderately overweight to moderately obese. That was good too.  
  
Hybrids, especially when they had the benefit of being near their linkmates, only suffered slight consequences when gaining weight, and it generally didn't cause any major issues. While their lifespans were similar to humans, they also remained youthful for a much greater proportion of it. Therefore, letting a hybrid pet get fat was merely considered harmlessly cute, a reflection of their ‘soft’ nature. In many cases, even an intentional outcome, as fat became a symbol of how much a hybrid was loved and spoiled.

* * *

  
Overall, Byleth found themself surprisingly happy with their new designation as the teacher… It was awkward at first, but the students were all kind and patient with their new teacher.  
  
Still, Byleth did find themself a bit dissatisfied… it was clear the hybrids had gotten very used to praise and affection, but Byleth wasn’t very used to giving it. They couldn’t help but feel terrible every time they failed to properly express their approval to their students, every time their praise accidentally came off as flat or insincere, every time a pat on the head felt stiff and unnatural. Byleth knew the students would almost certainly feel better if they could just be a little bit more friendly with them.  
  
But Byleth had always been a natural at saving money, not having much interest in luxuries, and they didn’t have to pay anything for their room or their meals… so they had an idea.  
  
Surely, with everyone already being pleasantly plump, and all of them raised to not really care about their diets… their stomachs would be an ideal way to their hearts.  
  
So, Byleth began diligently buying all sorts of treats in bulk, doing their best to remember and keep track of favorites.  
  
The effects were swift.  
  
It turned out the whole class was apparently very food-motivated.  
  
Not only did participation soar, but everyone seemed much more excited and motivated than before.  
  
There were smaller treats for smaller things. Good attendance, answering questions correctly, doing homework… That was perhaps worth a cookie, or some candy, or a bit of meat.  
  
But there were larger, richer treats, for bigger accomplishments, like getting A’s, or as an extra credit reward. Decadent things, even entire meals, sometimes.  
  
It definitely helped that the monastery had effectively unlimited food supplies. Magic allowed crops to be grown at an incredible pace, along with also vastly speeding up the growth and weight gain of farm animals. Hunger had been essentially eradicated across the land, only further increasing the frequency of plump-looking hybrids. Nor was anything considered sinful about being gluttonous, not when there was so much to go around.  
  
After all, Byleth felt like they had to be generous, to make up for the deficiency in other forms of praise.   
  
There were other small gifts and rewards too. Stickers and flowers, usually.  
  
But then there was another side-effect, one that Byleth hadn’t really expected…  
  
They started forming links with the students.  
  
Dimitri, seemingly part-Golden Retriever was first, his link coming in as a slow, inquisitive, ebbing wave at first, even somewhat shy... but then it came bursting in with the full force of his excitement and wonder as both parties fully realized what was going on.  
  
Then came Ashe, apparently part Husky… earnest, warm, bright, feeling as if Byleth’s very soul were receiving a hug.  
  
Then came Mercedes and Annette, both bunny girls; Sylvain, also part-bunny; Dedue, part-Mastiff; Ingrid, a catgirl, and finally, even Felix... a seemingly reserved catboy.  
  
Before Byleth knew it, by the end of their second month on the job… they’d already managed a link with every student they had.  
  
Byleth was met with confused but sincere congratulations from other staff members. It wasn’t unusual for a human teacher to link with some of their students… but what _ was _ unusual was going from having no links at all for a while to suddenly having all of them. If they were going to form, it hardly ever took so long… and it hardly ever happened to _ every _ student. If it did, they didn’t form within such a short time of one another.  
  
Still, Byleth supposed they were happy for the odd occurrence. It made it worlds easier to properly get their feelings and intentions across, for one…  
  
In a way, it also made the excessive treats unnecessary… a fact Byleth realized, but they couldn’t bring themself to get rid of or even cut back on the treats. Everyone was just so happy with them, and as their new linkmate, Byleth wanted to make them happy more than ever. When they were happy, so was Byleth, quite literally. They could feel the positivity of their students so strongly that it was hard to be upset about much of anything.  
  
And in forming so many links, it was soon decided that a generous raise was in order for Byleth… which just meant even more money for treats.  
  
But without cutting the treats back, it soon became clear that they were affecting more than just morale…  
  
After Byleth had been on the job for about three months, Dimitri walked in after class… Byleth looked up and couldn’t help but immediately feel color coming to their cheeks.  
  
Byleth knew Dimitri probably just wanted an excuse to come see them… It was rather obvious, with the way his tail started wagging as soon as he came in, and the way he seemed so obviously pleased to be alone with Byleth. That much was flattering, but not particularly shocking.  
  
What _ was _ an honest surprise was Byleth noticing just how tight Dimitri’s uniform had gotten…  
  
Of course, the ‘uniform’ was pretty much loungewear, reflecting the simple and laid back nature of the academy. But still, the shirt was so tight that Byleth could clearly see the indents of Dimitri’s belly button, lovehandles, and moobs, and it was riding up a bit too, showing off a sliver of pale, jiggly fat.  
  
Dimitri’s shorts weren’t faring much better, hugging his plump thighs and ass tightly. Dimitri was somewhat bottom heavy, after all. Bottom-heavy and traditionally ‘feminine’ fat distributions were more common among male hybrids than they were with human males.  
  
Even his face had softened just slightly, once Byleth took a good look… it made him look even cuter. Soft and pampered, like he deserved.  
  
“Professor, um…” Dimitri started, somewhat shyly. “I know our homework was to partner up and make cakes, to help us learn about baking… and Ashe and I did, but…” Dimitri let out a small whine. “I… ate the cake… The whole thing...”  
  
Byleth looked closer… Dimitri did look rather bloated, once they looked closer. The cakes they'd had to make had been relatively large. And Dimitri's uniform even still had traces of crumbs and frosting.  
  
“No one will want a pet with bad self control…” Dimitri whimpered, tail drooping. “But it smelled so amazing… and then it tasted even better. I wanted one little bite, but then I just couldn’t control myself…” Dimitri continued, looking down in shame.  
  
Byleth frowned, their heart feeling as if it’d been stabbed. They knew they’d probably become a bit too soft with their cute little lions, but they couldn’t stand to see Dimitri so upset.  
  
“That’s not true,” Byleth said quickly, thinking of how to spin the experience as a good thing. Although the link lessened the need to speak, it also ironically made it easier. It wasn’t so hard when Byleth wasn’t worried about being misunderstood. Part of them knew Dimitri might’ve actually had a point… but there had to be a bright side, didn’t there? “I’m sure plenty of people want a pet with such a good appetite. You’d eat anything they put in front of you. It’d flatter them,” Byleth explained.  
  
“...You think so?” Dimitri replied, still looking a bit skeptical.  
  
“Definitely,” Byleth replied, before reaching out and squeezing Dimitri’s growing tummy in both hands, briefly raising it up and letting it drop and briefly jiggle. Byleth smiled, noticing Dimitri’s tail starting to wag at the attention.  
  
“Besides, anyone who sees how cute and well-fed you are should know you need a lot of food. It’s their fault if they can’t keep up with a good appetite. You shouldn’t have to hold back. After all, I think it’s really cute that you love to eat so much. It’s even cuter that you’re getting all this nice new puppy fat. I mean, look how soft and cuddly you’re getting... If anything, I think you’ve actually been a really good boy, always finishing your meals and being so grateful for your treats,” Byleth explained, gently smiling as they continued to play with Dimitri’s fattened tummy.  
  
Dimitri blushed deeply, tail wagging even faster as he felt how loving and sincere Byleth was being. “T-thank you, Professor…”  
  
“As long as you make another cake, it’s not worth a punishment at all. In fact… I think some extra treats are in order. Better make sure you’re nice and full before you make that new cake. In fact, try to eat more from now on. Keep yourself full so projects like this don’t tempt you as badly.”  
  
“Of course! Professor, you’re so smart!” Dimitri gushed.  
  
“Thank you. But you’re a smart boy too, Dimitri, don’t forget that,” Byleth said kindly, only prolonging Dimitri’s blush. Hybrids and humans truly were about on the same level of intelligence… but a lot of pets did tend to become rather ditzy. It wasn’t so much a true lack of intelligence as it was a different mindset.  
  
Hybrids that’d decided to be pets tended not to particularly care about being smart, preferring to just focus on being good pets, and whatever else coincidentally interested them. Being less challenged and having fewer expectations put on them, along with trusting that they could always just rely on others, they became comfortable with not thinking too hard about most things. It was more of a habit than a true inability.  
  
Still, it also meant pet hybrids could be somewhat impressionable and naive, and they tended to be a bit childish when it came to certain behaviors...  
  
The next day, Byleth noticed something interesting, something that only confirmed that notion…  
  
Every last cake brought in was quite well-made, but looked like someone had already eaten some of it, and nearly every student ended up confessing that they had at least tasted a little… Felix was the only one who didn’t, and that was merely because he preferred savory food, rather than outstanding self-control on his part.  
  
Four other students besides Dimitri admitted to needing to make a whole new cake.  
  
Byleth couldn’t say they were surprised, especially when they zeroed in on everyone’s uniforms…  
  
Not a single student in the class actually seemed to have one that fit well anymore. All of them had plumped up considerably; thighs, bellies, and chests straining their uniforms considerably. Moreover, no one really seemed to care. Mercedes looked like her chest was threatening to spill out of her top, and Sylvain was looking like a surprisingly juicy pear, his hips even wider than Ingrid’s and threatening to burst out of his shorts… Not that his overhanging belly, with most of its fat concentrated in the lower regions, was far behind. Speaking of Ingrid, her flabby tummy was already bulging well ahead of her chest and hanging out of her uniform a bit, and she seemed to have taken first place as fattest girl without even fully realizing.  
  
Still, Byleth once again found a way to frame everyone’s behavior as a good thing. Making the extra cakes was proof that they were all responsible and hard working, and being so eager to taste them surely just meant that they were thorough in checking the quality of their work. Besides, they had no reason to be ashamed of having such wonderful appetites. There was clearly nothing wrong with them, their owners would just have to adjust and feed them more.  
  
Byleth couldn’t help but smile softly when everyone seemed cheered up by their placating words, tails wagging and expressions easing… Little did Byleth know, their innocuous attempt to protect their students’ feelings would set off a whole new chain of events...

* * *

  
The weight gain and general gluttony in their class noticeably became more severe over the next month, every single blue lion spurred on by Byleth’s advice and encouragement… on top of the steady flow of treats. Not only was Byleth making them, but Ashe, Annette, Mercedes, and Dedue all seemed to have started copying Byleth, showing their affection for their classmates through excessive gifts of food.  
  
The classes of every house had originally averaged out to rather similar weights… but by the time four months had passed, the Blue Lions were obviously fattest, by an average margin of around forty pounds… especially saying something when even the students of other houses had gained about fifteen to twenty pounds on average.  
  
All of the Blue Lions had started to jiggle with every step they took, and each needed to size up their uniforms at least twice… with a third resizing quickly on its way. They were more gluttonous than ever, eating around twice as much as their already rather plump and greedy classmates. None of them seemed to really mind, some even seeming proud of themselves… while others actually seemed rather oblivious. Mercedes always looked surprised every time her widening hips knocked things over, even as she kept baking and eagerly indulging in decadent sweets between every meal.   
  
Ashe ironically wanted to become a guard dog, only seeming to half-realize that he was undoubtedly at least a hundred pounds overweight… even though he honestly just looked harmless and adorably soft and flabby.  
  
Byleth had accidentally admitted as much through their link, and ended up unintentionally encouraging Ashe further in their attempts to rationalize it into a good thing. Looking so fat and cute would be the perfect thing to catch intruders and criminals off guard, after all. Plus, he wouldn’t be scary to children. It was perfect for him, clearly.  
  
Plus, all that weight would make it easier for him to overwhelm and immobilize an intruder, clearly… that part wasn’t really a lie, Ashe looked like he’d easily surpassed 250 pounds. He was starting to lapse from just being sort of chunky to getting soft and squishy all over, his whole body rounding and softening even beyond just his stomach and thighs.  
  
At the very least, Ashe, Felix, and Dedue were all actually enrolled in an extra course designed to teach them self-defense, which put them far above the typical level of exercise… which was essentially just whatever sparse physical activity the students did for fun, plus some mild exercises they did, mainly to ensure they at least had stamina to do things with their future owners. Fortunately, weight gain had lesser impact on a hybrid’s stamina than usual… but that didn’t mean all the impact was erased.  
  
Byleth couldn’t help but think it was amazingly cute to see their roly-poly students huff and puff and jiggle through their exercises, but they made sure to be extra kind and encouraging, knowing it must be a challenge when they were all so well-fed.  
  
Even for those in self-defense, you mostly wouldn’t know from looking at them… the exertion always made them hungrier, and so they ate even more than the Blue Lions ‘norm’ to compensate… and later on, they’d nap more often too. Not to mention, since it was an especially tough class, Byleth was always giving them plenty of extra treats and praise. Thanks to those factors, their weight gain wasn’t actually any slower than anyone else’s.  
  
Dedue was probably the only real case where it was actually noticeable… He was a large, stocky breed that could easily put on both fat and muscle. His arms and pecs were still obviously bulging with muscles, but they were clearly very squishy to the touch by default… and paired with great, soft thighs and a massive, doughy overhang of a gut.  
  
Regardless, Byleth likened him to a great big teddy bear. He wouldn’t hurt a fly until there was no other choice… and he was lovely to cuddle with… although that just made it clear that yet another thing had changed, by the end of the fourth month.  
  
Byleth had started getting more physically affectionate with their students.  
  
It was still all completely platonic, but Byleth couldn’t help but feel a little guilty about it. Was it unprofessional to cuddle with the students? It didn’t feel wrong emotionally speaking… in that sense, Byleth actually felt like they were doing the right thing. They still weren’t the best with words, so it felt like cuddling and extra hugs and things like that were just another way to really let the students know how much Byleth cared. Besides, they were all hybrids. It was normal for hybrids to be more accustomed to lots of physical contact. Byleth saw them cuddle one another and play with each other’s tummies plenty of times.  
  
Even Felix would let Annette or Sylvain play with his new fat, typically as they giggled and alternated between compliments and playful teasing… he’d even started letting Ashe pet him, too.  
  
Sometimes they’d even all have nap time together after class, since Byleth figured it’d help them bond. What’d started out as sleeping spread out across the floor had progressed to big, soft cuddle piles, nearly always centered on Byleth.  
  
While it would be a stretch to say any of the students were unhappy at the academy, it also wouldn’t be a stretch to say that the Blue Lions were starting to seem like the happiest. They were always so excited to go to class, and always gushing over Byleth. Always unabashedly stuffing their faces, then happily giving each other belly rubs and cuddles. They’d play and nap together all the time, and something about them… just seemed closer and more relaxed, compared to before.  
  
They already seemed like pets anyone would be thrilled to have. A soft, docile, loving, playful group of adorable gluttons.  
  
So of course, it only made sense that some of the others would begin getting curious or even outright jealous, no longer wanting the Blue Lions hogging Byleth for themselves.  
  
And that was how by the beginnings of month five, Byleth was suddenly looking at Caspar, Linhardt, Raphael, Hilda, Petra, and even Claude wanting to join their house.  
  
Byleth had been under the impression Claude couldn’t or wouldn’t do such a thing, being designated the leader of his own house… but given the relaxed nature of the school, they supposed such things didn’t matter as much as they thought.  
  
Although a part of Byleth was nervous… they’d become so used to things that they were mostly just excited. Byleth would never turn down more cute little hybrid pups to spoil… Even if the students were all actually very close in age to Byleth, the difference in how conventionally ‘mature’ the students acted was pretty clear. As far as emotional maturity, obedience, and how to get along and resolve disputes, the students were genuinely quite composed and adult-like… but in most other behaviors, they came off as significantly younger.  
  
Everyone’s self-control issues with food were as prominent as ever, and they all had varying degrees of naivety and ditziness… The students also tended to be a bit lazy and undisciplined outside of class, but their strong desire to please Byleth kept them going. Not to mention, Byleth had started to notice the students seemed incredibly trusting and uncritical towards them, happily believing whatever they said and obeying commands under any context, not just during class. Byleth resolved to do their best not to abuse that realization, even unintentionally. But regardless, they weren’t too worried. In large part, being linked to Byleth was what made the students so fond and trusting towards their teacher. They’d easily be able to feel it if there were any ill-will.  
  
Byleth had to do their best to make their newly recruited students feel welcome… and perhaps fatten them up a bit.  
  
Good pets were even better when they were extra soft and spoiled with treats, after all. 


End file.
